output_add_rewrite_var in PHP

output_add_rewrite_var — Add URL rewriter values
Syntax: bool output_add_rewrite_var ( string $name , string $value )
This function adds another name/value pair to the URL rewrite mechanism.
The name and value will be added to URLs (as GET parameter) and forms (as hidden input fields) the same way as the session ID when transparent URL rewriting is enabled with session.use_trans_sid.
Please note that absolute URLs (http://example.com/..) aren't rewritten.
This function's behavior is controlled by the url_rewriter.tags php.ini parameter.
Note: Calling this function will implicitly start output buffering if it is not active already.
Parameters: 
name:The variable name.
value:The variable value.
Returns TRUE on success or FALSE on failure.
Example #1

<?php
output_add_rewrite_var('var', 'value');

// some links
echo '<a href="file.php">link</a>
<a href="http://example.com">link2</a>';

// a form
echo '<form action="script.php" method="post">
<input type="text" name="var2" />
</form>';

print_r(ob_list_handlers());
?>
Output:

<a href="file.php?var=value">link</a>
<a href="http://example.com">link2</a>

<form action="script.php" method="post">
<input type="hidden" name="var" value="value" />
<input type="text" name="var2" />
</form>

Array
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    [0] => URL-Rewriter
)